Avalanches: the ever-present danger


Tuesday, April 3, 2018 – Updated at 11: 14h.

The avalanches of
spring are less dangerous than powder or plate snow … Well, this is more than a myth.

93 percent of
the victims of an avalanche, it is by an avalanche of plaque that has
unchained the skier himself or one of his companions. The
spring snow avalanches are very dense and with very high capacity
destructive, but they occur at a particular time of the day, in which
it is difficult to match a skier "who was passing by
there. "Like if we want to cross a road where
only one truck passes a day, it will be very difficult to cross just
at the moment the truck passes by. That's why they rarely cause
victims.

There are only two possibilities that make the avalanches of
spring are more dangerous:

  • That you
    Stand still on the road waiting for the truck to arrive: as
    a refuge (Respomuso, Góriz, etc).

  • That you go
    along the road, crossing it through the center on its axis, until
    find yourself with the truck: do a runner on a hot day or
    of rain or the first day after a snowfall. Day in which everything will go
    purging by the corridor. Going up it, you will be exposed all the
    weather.

Only the
skiers can trigger an avalanche

Any overload
can trigger an avalanche of plaque, be it a skier, a chamois,
a snowmobile or a mountaineer who climbs on foot. But usually,
in the Pyrenees and in the mountains of the Iberian Peninsula, are the
skiers the main triggers of plate avalanches. This
occurs as soon as four requirements are met:

  • One layer
    fragile under the cohesive snow cover on which we are
    skiing This information can only be found after reading the parts of
    snow and avalanches of the nivólogos, that previously have studied a
    column of snow isolating it with saws and a shovel, checking its
    stability and configuration of the snow crystals of each
    inner layer.

  • One
    inclination of 30º or more, especially if we get into the range
    critical inclination, between 35 and 40º.

  • And, for
    course, an overload. It will be weak if it is a single skier,
    when the group keeps the safety distance between skiers,
    going up or down. But we can create a strong overload if
    we climb all together on the slope, without saving a minimum
    20 meters safety distance between skiers. The overload
    will be much greater if that grouping is done in the descent, because
    skiing and jumping generate much greater overloads than
    progress upwards by focusing.

In mountains of
low altitude as Gredos or Guadarrama there is no danger

The zero risk does not
it exists
in the mountains and we can trigger avalanches at any height.
Even so, it is true that the lower the level, the lower the
danger by avalanches. Because at low levels the winds are less
intensity and remember that the wind is that main generator of
plates. And also, at high altitudes, the temperatures are colder
(worse transformation of snow crystals) and snowfall are
greater. In general, at higher altitudes, greater danger, but never
the danger will disappear by going to lower levels.

Bulletins of
Avalanche risk are exaggerated

There was a time in the
that the official bulletins, pulled "upward", to
cover yourself in health, so that you would see a whole season with
Danger level 3 and many day level 4, without really being. Each
day the bulletins are made better and there are more nivologists doing
Snow cuts on the ground and with good knowledge of
nology and meteorology, so that each year they are more
rigorous and emit a level of danger commensurate with the real.

It must be said that
the bulletins are regional and not local, so that in valleys
The danger can sometimes be greater or less than the risk
regional global So if we have valleys with danger level 2
and others with level 3, the bulletin will always announce the greatest danger
of the two, being then the mountaineer who must decide in what
local valleys the maximum level hazard expressed in the
bulletin.

The ARVA does not work
Not at all

The important thing is not
Take the ARVA, but not have to use it. Much of the
avalanche victims are partially on the surface and not
They need ARVA for their release. Another part is buried with
great traumatisms, incompatible with life. But there is a third
of victims that are buried at one or two meters, without
polytrauma, which will die without being located before the first
15 to 20 minutes by his companions. And these, in addition to carrying ARVA
(DVA), they must know how to use it, have practiced, have attended
courses and know how to do an effective search.

They must also
take a probe to fine-tune the paleo site and a good shovel,
make a strategic paleo, which can last from eight to ten
minutes according to depth. You can not go out to the winter mountain
without DVA, shovel and probe. And then, once in the bush, we'll have to
behave as if we did not wear anything, tracing safely and
looking for low risk areas

It's almost impossible
deduce where an avalanche can be triggered

It is not easy to know
where an avalanche is going to occur, but we can intuit the
risk zones, according to the news bulletin, as we see
where the wind blew (looking at the cornices, the snow blown,
etc), depending on the slope of the slope, etc. Then you have to
know that, in areas where we can unleash a plaque, in nine of
every ten times, it will not be triggered. But that does not want
say that we have done well. We go home with the most lesson
learned It has gone well, but we have done badly. It's like having
a pistol with ten cameras and only one bullet loaded. The majority
of the times it will not fire, but in the end it will. From
way that it is convenient to go reading the snow and avoiding those areas
prone to an avalanche of plaque, not to play with luck. Someday
It can go wrong.

Avalanches only
occur on very steep slopes

Below 25-30º
it is difficult to trigger an avalanche, due to lack of slope or
inclination. But above 45-50º, the slope is so high,
that the snow is purging as it snows and does not accumulate in
Cohesive plate shape.

It is in the range of 30
at 45º where the risk is maximum and especially in the range of
fever of the people, of 38 to 40º (not of fever or temperature,
but of inclination). In that tilt, the snow stays in
a critical balance. A balance that we can break only with
let a skier pass over

Where has
fallen an avalanche there is no immediate risk of another fall

Previous prints
they do not ensure that a shovel is safe from avalanches. Sometimes a shovel
you need not one but three or four different surcharges to go
breaking their anchors and, finally, with the fourth or fifth
overload, finally come down. Therefore, although we see a shovel
that has already been skied, without falling anything, this does not guarantee that it is
a safe shovel.

Another issue is
skiing through the snow bed that has left an avalanche. With
exceptions, it is usually a safe surface. If we are in the field
of avalanches and a companion has triggered an avalanche of plaque, if
We want to go down the same slope (which will have a similar danger to
the plate) the most prudent thing will be to get down precisely for the
bed where the plate has gone down, skiing on the surface that
has been uncovered, that was the surface on which it has been
Sliding the top plate.

                

Risk management

                                

 Avalanches. Risk management "src =" http://www.libreriadesnivel.com/static/img/978-84-9829-073-8_g.jpg "style =" width: 125px; height: 168px; border-width: 1px; border-style: solid; margin: 5px; float: left; "/> </p>
<h5>
</h5>
<p> 3 x 3 Avalanches </p>
<p> <strong> Risk management in winter sports </strong>  </p>
<p> by Werner Munter </p>
<p> Elaborated around the 3×3 method – a formula that crosses three filters and three factors – and the reduction method, this book offers an excellent methodology that facilitates the assessment of avalanche risk </p>
<p>                                </p></div>
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